The present invention relates to a process for producing an alkyl-substituted aromatic hydrocarbon. More specifically, it relates to a process for producing an alkyl-substituted aromatic hydrocarbon at high yields industrially advantageously.
An alkyl-substituted aromatic hydrocarbon is useful as an intermediate for the preparation of a polymer and medicaments. As a process for producing such an alkyl-substituted aromatic hydrocarbon, there are conventionally known the Friedel-Crafts reaction in which an aromatic hydrocarbon is alkylated in a liquid phase in the presence of anhydrous aluminum chloride as a catalyst, a gaseous-phase reaction in which an aromatic hydrocarbon is alkylated in the presence of a solid silica alumina as a catalyst, or the like.
Since, however, the Friedel-Crafts reaction generally produces a large amount of high-boiling compound(s) as a by-product, the intended alkyl-substituted aromatic hydrocarbon cannot be produced at high yields. The other gaseous phase reaction using a solid silica alumina catalyst requires a high temperature, and various side reactions occur. Therefore, the yield of the intended product is similarly low.
The Mar. 6, 1991 issue of Nikkan Kogyo Shinbun (The Business and Technology Daily News) reported that when an acidic catalyst prepared by partially replacing hydrogen in tungstophosphoric acid with cesium is used in the production of dodecylphenol from phenol, it exhibits 20 to 60 times greater activity than sulfuric acid (catalyst) per weight and 100 times higher activity than zeolite per weight. This report also said that even a potassium salt, too, is considered effective as catalyst.